Lubrication groove for deep groove ball bearing

ABSTRACT

A deep groove ball bearing assembly is disclosed. The assembly includes an inner bearing ring defining an inner race, an outer bearing ring defining an outer race, and a plurality of rolling elements supported on the inner race and the outer race. A shaft is supported on a radially inner surface of the inner bearing ring, and a housing is supported on a radially outer surface of the outer bearing ring. The assembly includes a contact surface on at least one of: the inner bearing ring, the outer bearing ring, the shaft, or the housing. The contact surface includes at least one lubrication groove.

FIELD OF INVENTION

The present invention relates to a deep groove ball bearing.

BACKGROUND

Deep groove ball bearings are well known, particularly in the automotivefield. Deep groove ball bearings are used in automotive transmissions,especially for continuously variable transmissions or hybridtransmission or e-axles. These known types of bearings experience creepdue to high speed and heavy loads. In particular, the outer bearing ringexperiences creep, which causes fretting and wear in the outer housing,typically formed from aluminum.

Known solutions for addressing bearing creep include applying a coatingto the bearing components, or require the use of an angular contactbearing with a biasing element to provide a preload. These solutions arerelatively expensive and require additional assembly steps and handling.

Known solutions for addressing creep or thermal expansion of bearingassemblies are disclosed in US Pub 2012/0093453; U.S. Pat. Nos.8,684,608; 5,028,152; and US Pub. 2009/0080824.

It would be desirable to provide a cost-effective solution foraddressing fretting and wear in deep groove ball bearings that does notaffect load capacity and is relatively simple to assemble.

SUMMARY

A deep groove ball bearing assembly is disclosed. The assembly includesan inner bearing ring defining an inner race, an outer bearing ringdefining an outer race, and a plurality of rolling elements supported onthe inner race and the outer race. A shaft is supported on a radiallyinner surface of the inner bearing ring, and a housing is supported on aradially outer surface of the outer bearing ring. The assembly includesa contact surface on at least one of: the inner bearing ring, the outerbearing ring, the shaft, or the housing. The contact surface includes atleast one lubrication groove.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing Summary and the following detailed description will bebetter understood when read in conjunction with the appended drawings,which illustrate a preferred embodiment of the invention. In thedrawings:

FIG. 1A is a cross-sectional view of a deep groove ball bearingincluding grooves formed in an outer bearing ring.

FIG. 1B is an exploded view of the deep groove ball bearing of FIG. 1A.

FIG. 1C is a cross-sectional view of an outer bearing ring of the deepgroove ball bearing of FIG. 1A.

FIG. 2A is a cross-sectional view of a deep groove ball bearingincluding grooves formed in a housing.

FIG. 2B is an exploded view of the deep groove ball bearing of FIG. 2A.

FIG. 3A is a perspective view of an outer bearing ring according toanother embodiment.

FIG. 3B is a perspective view of an outer bearing ring according toanother embodiment.

FIGS. 3C-3G are cross-sectional views of grooves according to varyingembodiments.

FIG. 4 is a cross-sectional view of a deep groove ball bearing includinggrooves formed in an inner bearing ring.

FIG. 5 is a cross-sectional view of a deep groove ball bearing includinggrooves formed in a shaft.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Certain terminology is used in the following description for convenienceonly and is not limiting. The words “front,” “rear,” “upper” and “lower”designate directions in the drawings to which reference is made. Thewords “inwardly” and “outwardly” refer to directions toward and awayfrom the parts referenced in the drawings. “Axially” refers to adirection along the axis of a shaft. A reference to a list of items thatare cited as “at least one of a, b, or c” (where a, b, and c representthe items being listed) means any single one of the items a, b, or c, orcombinations thereof. The terminology includes the words specificallynoted above, derivatives thereof and words of similar import.

Referring to FIGS. 1A-1C, a first embodiment of a deep groove ballbearing assembly 10 is illustrated. The deep groove ball bearingassembly 10 includes an inner bearing ring 12 defining an inner race 13,an outer bearing ring 14 defining an outer race 15, and a plurality ofrolling elements 16 supported on the inner race 13 and the outer race15. The rolling elements 16 can be supported by a cage 17. A shaft 18 issupported on a radially inner surface 19 of the inner bearing ring 12. Ahousing 20 is supported on a radially outer surface 21 of the outerbearing ring 14. Generally, a contact surface is defined of at least oneof: the inner bearing ring 12, the outer bearing ring 14, the shaft 18,or the housing 20. The contact surface includes at least one lubricationgroove 25.

The lubrication groove 25 addresses fretting and wear problems in deepgroove ball bearings but reducing contact areas between facing contactsurfaces, while avoiding any negative impact on load capacity orexpensive coating materials. The lubrication groove 25 also provides amore reliable supply of lubricant to facing contact surfaces, whichreduces fretting and wear.

Specifically, as shown in FIGS. 1A-1C, the grooves 25 are formed in theouter bearing ring 14. As shown in FIGS. 1A-1C, the housing 20 includesa lubrication conduit 30. The lubrication conduit 30 extends from an endface 31 of the housing 20 and extends to a radially inner surface of thehousing 20 that faces the grooves 25 on the outer bearing ring 14.

In the embodiment of FIGS. 1A-1C, the outer bearing ring 14 can have anincreased outer diameter compared to existing out bearing rings thatlack any lubrication grooves 25. In one embodiment, the outer diameterof the outer bearing ring 14 is increased 1.0-2.0 mm compared toexisting bearing rings to help further reduce creep.

As shown in FIGS. 2A and 2B, a second embodiment of a deep groove ballbearing 110 is illustrated. Similar features from FIGS. 1A-1C areindicated by identical reference numerals. In this embodiment, thehousing 120 includes the lubrication grooves 125 on a contact surfacefacing the outer bearing ring 114. As shown in FIG. 2A, the housing 120also includes the lubrication conduit 130 extending from an outersurface 131 to a contact surface of the housing 120 defining thelubrication grooves 125.

In this embodiment, a contact surface 122 of the housing 120 has a firstaxial extent (d₁), the at least one groove 125 includes a plurality ofgrooves 125, and the plurality of grooves have a second axial extent(i.e. a sum of each individual axial extent of each groove) that is atleast 15% of the first axial extent (d₁). In one embodiment, the secondaxial extent is 15%-33% of the first axial extent (d₁).

In one embodiment, the grooves 25 a, 25 b are angled relative to acircumferential plane. FIGS. 3A and 3B illustrate grooves 25 a, 25 bformed on a radially outer surface of an outer bearing ring 14 a, 14 b.A pitch of the grooves 25 a in FIG. 3A is 4-6 mm. A pitch of the grooves25 b in FIG. 3B is 18-20 mm. One of ordinary skill in the art wouldrecognize that the pitch, size, quantity, and other variables regardingthe grooves 25 a, 25 b can be varied depending on a specificapplication's requirements. As shown in FIG. 3A, the at least one groove25 a includes a single groove extending for at least three revolutions.As shown in FIG. 3B, the at least one groove 25 b includes at leastthree grooves, and each of the at least three grooves extends for asingle revolution.

As shown in FIGS. 3C-3G, the profile of the grooves 25 c-25 f can bevaried. In FIG. 3C, the groove 25 c has a generally curved, half-circleprofile. In FIG. 3D, the groove 25 d includes a generally triangularprofile with curved edges. In FIG. 3E, the groove 25 e has a generallytrapezoidal profile with a relatively flat base surface. The groove 25 fof FIG. 3F includes a generally rectangular profile with flat sidesurfaces and a flat base surface. The groove 25 g of FIG. 3G has asimilar profile as groove 25 c but has a deeper profile with elongatedside wall surfaces.

FIG. 4 illustrates an alternative embodiment of a deep groove ballbearing 210 in which the lubrication grooves 225 are formed on aradially inner surface of the inner bearing ring 212, and thelubrication grooves 225 face the shaft 218.

FIG. 5 illustrates an alternative embodiment of a deep groove ballbearing 310 in which lubrication grooves 325 are formed on a radiallyouter surface of the shaft 318, and the lubrication grooves 325 face theinner bearing ring 312.

One of ordinary skill in the art would recognize from the presentdisclosure that lubrication grooves can be formed on any of the contactsurfaces of the deep groove ball bearing assembly. These lubricationgrooves reduce fretting and wear, which negatively impact performance ofthe deep groove ball bearing assemblies.

Having thus described the present invention in detail, it is to beappreciated and will be apparent to those skilled in the art that manyphysical changes, only a few of which are exemplified in the detaileddescription of the invention, could be made without altering theinventive concepts and principles embodied therein. It is also to beappreciated that numerous embodiments incorporating only part of thepreferred embodiment are possible which do not alter, with respect tothose parts, the inventive concepts and principles embodied therein. Thepresent embodiment and optional configurations are therefore to beconsidered in all respects as exemplary and/or illustrative and notrestrictive, the scope of the invention being indicated by the appendedclaims rather than by the foregoing description, and all alternateembodiments and changes to this embodiment which come within the meaningand range of equivalency of said claims are therefore to be embracedtherein.

LOG OF REFERENCE NUMERALS

-   -   Deep groove ball bearing 10, 110, 210, 310    -   Inner bearing ring 12, 212, 312    -   Inner race 13    -   Outer bearing ring 14, 14 a, 14 b, 114    -   Outer race 15    -   Rolling elements 16    -   Cage 17    -   Shaft 18, 218, 318    -   Housing 20, 120    -   Radially outer surface of outer bearing ring 21    -   Lubrication groove 25, 25 a, 25 b, 125, 225, 325    -   Lubrication conduit 30, 130    -   End surface 31    -   Contact surface 122

What is claimed is:
 1. A deep groove ball bearing assembly comprising:an inner bearing ring defining an inner race; an outer bearing ringdefining an outer race; a plurality of rolling elements supported on theinner race and the outer race; a shaft supported on a radially innersurface of the inner bearing ring; a housing supported on a radiallyouter surface of the outer bearing ring; a contact surface on at leastone of: the outer ring or the housing, the contact surface includes aplurality of grooves; and at least one lubricant conduit is defined inthe housing and extends between a housing end surface and the contactsurface, such that the at least one lubricant conduit terminates at thecontact surface in a region between two grooves of the plurality ofgrooves.
 2. The deep groove ball bearing assembly of claim 1, whereinthe plurality of grooves are formed on a radially inner surface of thehousing.
 3. The deep groove ball bearing assembly of claim 1, whereinthe plurality of grooves includes at least three grooves, and each ofthe at least three grooves extends for a single revolution.
 4. The deepgroove ball bearing assembly of claim 1, wherein the contact surface ofthe housing has a first axial extent, and the plurality of grooves havea second axial extent that is at least 15% of the first axial extent. 5.The deep groove ball bearing assembly of claim 1, wherein the pluralityof grooves are formed on the radially outer surface of the outer bearingring.
 6. The deep groove ball bearing assembly of claim 1, wherein theplurality of grooves are pitched grooves.
 7. A deep groove ball bearingassembly comprising: an inner bearing ring defining an inner race; anouter bearing ring defining an outer race; a plurality of rollingelements supported on the inner race and the outer race; a shaftsupported on a radially inner surface of the inner bearing ring; ahousing supported on a radially outer surface of the outer bearing ring;and a contact surface on a radially inner surface of the housing,wherein the contact surface includes a plurality of grooves, and thehousing includes at least one lubricant conduit extending between anaxial end surface and the radially inner surface of the housing, whereinthe axial end surface of the housing includes a plurality of lubricationinlets spaced apart from each other in a circumferential direction. 8.The deep groove ball bearing assembly of claim 7, wherein the housing isformed from aluminum and the outer bearing ring is formed from steel. 9.The deep groove ball bearing assembly of claim 7, wherein the pluralityof grooves are angled relative to a circumferential plane.